ABACUS:the world's first computer made in 300b.c.This computer was used to aided addition and subtractiond .Five in the lower area represented the fingers and two above represented two hands.logarithms:was the worlds second computer made by John Napier.which allowed multiplication using addition. Each operand was looked up in a log table. The idea led directly to the slide rule (1632, England) which we (engineers) used during the Apollo program.
BLAISE PASCAL: Even Leonardo da Vinci had a design for a gear-driven calculating machine. Blaise Pascal (France, 1642) built the first gear-driven calculator (actually just an adder). It unfortunately made mistakes because you couldn’t make gears with enough precision back then.
Mathematician Gottfried Leibniz (Germany, about 1650) built a calculator that could add, subtract, multiply, and divide. Leibniz even suggested that binary numbers would be useful in calculating. He invented the modern binary numbering system (and a lot of other things, including co-inventing calculus).
Mathematician Gottfried Leibniz (Germany, about 1650) built a calculator that could add, subtract, multiply, and divide. Leibniz even suggested that binary numbers would be useful in calculating. He invented the modern binary numbering system (and a lot of other things, including co-inventing calculus).
Joseph Jacquard (France, 1801) invented a powered loom that used punched wooden cards to automatically weave incredibly detailed patterns including pictures and text. You could think of this as being the first “read only memory”. It was certainly the predecessor of the computer punch card. Power for the loom came from water wheel or steam engine.
The English mathematician Charles Babbage (about 1830) proposed a steam-driven calculating machine the size of a room. He called it a “Difference Engine”. It would compute tables of numbers, like logarithms or navigation tables. He received a great deal of government funding for the project because it had military and commercial importance. It was never finished, so Babbage (like any government scientist) came up with an even bigger project called the Analytic Engine. It would have been powered by 6 steam engines and programmable, thanks to Jacquard’s punch cards. Babbage even proposed that punched paper could be used rather than wooden cards.
The English mathematician Charles Babbage (about 1830) proposed a steam-driven calculating machine the size of a room. He called it a “Difference Engine”. It would compute tables of numbers, like logarithms or navigation tables. He received a great deal of government funding for the project because it had military and commercial importance. It was never finished, so Babbage (like any government scientist) came up with an even bigger project called the Analytic Engine. It would have been powered by 6 steam engines and programmable, thanks to Jacquard’s punch cards. Babbage even proposed that punched paper could be used rather than wooden cards.
Babbage’ friend Ada Byron, daughter of poet Lord Byron, began “writing programs” for the unbuilt machine. The British government refused to get involved with this project, but Ada became the first computer programmer. She invented the subroutine and used “looping”, the re-use of a group of instructions. The computer Ada computer programming language is named after her.
Boolean Algebra
In about 1847 a fellow was working on "symbolic logic". He seems to have felt that we could use mathematical reasoning to make our decisions. "If Suzy is off work AND I have $5 OR I can borrow it, we can go to the movies". Digital computers rely on the functions (operations) of Boolean Algebra like AND, OR, XOR and NOT. George Boole its inventor probably hoped that it might be possible for humans to act logically.
In about 1847 a fellow was working on "symbolic logic". He seems to have felt that we could use mathematical reasoning to make our decisions. "If Suzy is off work AND I have $5 OR I can borrow it, we can go to the movies". Digital computers rely on the functions (operations) of Boolean Algebra like AND, OR, XOR and NOT. George Boole its inventor probably hoped that it might be possible for humans to act logically.
The "next big thing" was America’s. Tabulating the US census of 1880 took seven and a half years. Results for the 1890 census might not be available before the 1900 census was taken! Herman Hollerith invented a process using Jacquard's punched cards to do the work. A card reader sensed holes in the cards, a gear driven counter (Pascal's idea, like a car odometer) kept results, and a wall full of dial indicators displayed them. Hollerith built a company which eventually became IBM. IBM’s “Hollerith” cards became ubiquitous.
Here’s an 1890s era IBM card. By the way, the little bits of paper punched out of the card are "chad". You may remember an election result rested on what to do about the “hanging chad”. The expression "do not fold, spindle, or mutilate" came from something often stamped on the cardsElectro-mechanical computers
IBM’s mechanical calculators could actually only add and subtract. (They did multiplication by repeated addition.) As World War II began, the U.S. military needed a calculator capable of “scientific calculations” in order to make ballistic firing tables for big naval guns, among other things. This was done by the “human computers” still. Harvard and IBM built the Mark I computer in 1944 to do the job. This was a mechanical/electrical digital computer which was programmable by punched tape. It did not use binary arithmetic. It used switches, relays, rotating shafts, and clutches and weighed 5 tons and was 50 feet long. The Mark I could add or subtract in three-tenths of a second, multiply in four seconds, and divide in ten seconds. It had about 750,000 components but could only store 72 numbers!
Here’s an 1890s era IBM card. By the way, the little bits of paper punched out of the card are "chad". You may remember an election result rested on what to do about the “hanging chad”. The expression "do not fold, spindle, or mutilate" came from something often stamped on the cardsElectro-mechanical computers
IBM’s mechanical calculators could actually only add and subtract. (They did multiplication by repeated addition.) As World War II began, the U.S. military needed a calculator capable of “scientific calculations” in order to make ballistic firing tables for big naval guns, among other things. This was done by the “human computers” still. Harvard and IBM built the Mark I computer in 1944 to do the job. This was a mechanical/electrical digital computer which was programmable by punched tape. It did not use binary arithmetic. It used switches, relays, rotating shafts, and clutches and weighed 5 tons and was 50 feet long. The Mark I could add or subtract in three-tenths of a second, multiply in four seconds, and divide in ten seconds. It had about 750,000 components but could only store 72 numbers!
Grace Hopper was a programmer on the Mark I. She went on to develop the first high level computer language, COBOL (Common Business Oriented Language) in the early 1950s. She is also credited with having found the first actual computer “bug”, a dead moth blocking the paper tape reader--so she also became the first debugger. But, I’m getting way ahead of myself.
As WWII began, Germany was using a class of electro-mechanical cipher machines called “Enigma” to encode and decode shortwave radio transmissions. If the allies could decrypt the code they would know what instructions were sent to the Wermacht, where the Nazi U-Boats were located, and so on. An Enigma machine is shown on the right. By 1938 the Polish had developed an electro-mechanical device they called a bomb to speed comparison of thousands of possible solutions to the code used in a given message. They gave British intelligence a copy of an Enigma machine and a bomb in 1939. At the British code-breaking center Bletchley Park, Mathematician Alan Turing continued the development of much larger and more complicated bombs, which were now called “bombe”. A partially completed Bombe is shown on the left.
As WWII began, Germany was using a class of electro-mechanical cipher machines called “Enigma” to encode and decode shortwave radio transmissions. If the allies could decrypt the code they would know what instructions were sent to the Wermacht, where the Nazi U-Boats were located, and so on. An Enigma machine is shown on the right. By 1938 the Polish had developed an electro-mechanical device they called a bomb to speed comparison of thousands of possible solutions to the code used in a given message. They gave British intelligence a copy of an Enigma machine and a bomb in 1939. At the British code-breaking center Bletchley Park, Mathematician Alan Turing continued the development of much larger and more complicated bombs, which were now called “bombe”. A partially completed Bombe is shown on the left.
Another candidate for the grandfather of modern computers was the Colossus, also built by the British code breakers at Bletchley Park. Colossus was completed in 1944. Britain was the world leader in mechanical/electrical/electronic machines for code breaking. Colossus was a digital, partially electronic computer but it was certainly not a general purpose, programmable machine.
Electronic Computers
Maybe the father of the all-electronic digital computer is ENIAC (Electronic Numerical Integrator and Calculator) built by the University of Pennsylvania in 1943-45 by John Mauchly and J. Presper Eckert. (There are other candidates. Look up the Atanasoff-Berry Computer developed at my alma mater, Iowa State University for example.) Mauchly and Eckert promised the war department that they could replace all the women employed calculating the firing tables for the army's artillery guns.
ENIAC was huge, and it worked, although not before the end of the war. It filled a 20 by 40 foot room, weighed 30 tons, and used 17,468 vacuum tubes. It was silent, but hot—150 kW of power, and therefore heat! At first it required about 8 hours of repair for every 8 hours of use. Off-the-shelf IBM paper card readers fed data into the computer and it was reprogrammed by hundreds of patch cords and setting 3000 switches.
ENIAC could only hold 20 numbers at a time, but with no moving parts it was hugely faster than the Mark I. For example a multiplication only required 2.8 mS (thousandths of a second). The system clock was 100 kHz. ENIAC’s first task was computations on the hydrogen bomb
ENIAC was a pain to reprogram, requiring changes to all those patch cords and switches. It took days. Eckert and Mauchly next teamed up with mathematician John von Neumann to design EDVAC, perhaps the first stored program computer. After ENIAC and EDVAC came ILLIAC, JOHNNIAC, and, not surprisingly MANIAC.
Electronic Computers
Maybe the father of the all-electronic digital computer is ENIAC (Electronic Numerical Integrator and Calculator) built by the University of Pennsylvania in 1943-45 by John Mauchly and J. Presper Eckert. (There are other candidates. Look up the Atanasoff-Berry Computer developed at my alma mater, Iowa State University for example.) Mauchly and Eckert promised the war department that they could replace all the women employed calculating the firing tables for the army's artillery guns.
ENIAC was huge, and it worked, although not before the end of the war. It filled a 20 by 40 foot room, weighed 30 tons, and used 17,468 vacuum tubes. It was silent, but hot—150 kW of power, and therefore heat! At first it required about 8 hours of repair for every 8 hours of use. Off-the-shelf IBM paper card readers fed data into the computer and it was reprogrammed by hundreds of patch cords and setting 3000 switches.
ENIAC could only hold 20 numbers at a time, but with no moving parts it was hugely faster than the Mark I. For example a multiplication only required 2.8 mS (thousandths of a second). The system clock was 100 kHz. ENIAC’s first task was computations on the hydrogen bomb
ENIAC was a pain to reprogram, requiring changes to all those patch cords and switches. It took days. Eckert and Mauchly next teamed up with mathematician John von Neumann to design EDVAC, perhaps the first stored program computer. After ENIAC and EDVAC came ILLIAC, JOHNNIAC, and, not surprisingly MANIAC.
Transistors
In 1947 IBM commissioned a study which concluded that six electronic digital computers would be sufficient to satisfy the computing needs of the entire United States. There are six computers in my car today—all more powerful and much, much faster than the ENIAC. Another thing that happened in 1947 was that William Shockley and others at Bell Labs built the first transistor. It would change everything. The British call electron tubes “valves” because a small electrical input voltage controls a much larger output current. Transistors are electronic valves too, only they are smaller, use much less power, and are more reliable than tubes. The story at this point moves toward the Integrated Circuit, which consists of many transistors on a single piece of silicon.
In 1947 IBM commissioned a study which concluded that six electronic digital computers would be sufficient to satisfy the computing needs of the entire United States. There are six computers in my car today—all more powerful and much, much faster than the ENIAC. Another thing that happened in 1947 was that William Shockley and others at Bell Labs built the first transistor. It would change everything. The British call electron tubes “valves” because a small electrical input voltage controls a much larger output current. Transistors are electronic valves too, only they are smaller, use much less power, and are more reliable than tubes. The story at this point moves toward the Integrated Circuit, which consists of many transistors on a single piece of silicon.
